Polyorganosiloxane production method

ABSTRACT

Provided is a method of producing a polyorganosiloxane, including bringing a polyorganosiloxane produced by using a transition metal-based catalyst into contact with an adsorbent having an average pore diameter of 1,000 Å or less.

TECHNICAL FIELD

The present invention relates to a method of producing apolyorganosiloxane, and more specifically, to a method of producing apolyorganosiloxane to be used as a raw material for apolycarbonate-polyorganosiloxane copolymer.

BACKGROUND ART

A polycarbonate is excellent in mechanical properties such astransparency and impact resistance, and hence has been widely utilizedin industries typified by an automobile field, an OA field, andelectrical and electronic fields. Commonly, a homopolycarbonate using2,2-bis(4-hydroxyphenyl)propane [common name: bisphenol A] as a dihydricphenol serving as a raw material has been generally used as a typicalpolycarbonate. A polycarbonate-polyorganosiloxane copolymer using apolyorganosiloxane as a copolymerizable monomer has been known forimproving the physical properties of the homopolycarbonate such as flameretardancy and impact resistance (see Patent Documents 1 to 3).

As the polyorganosiloxane to be used as the copolymerizable monomer uponproduction of the polycarbonate-polyorganosiloxane copolymer, there hasbeen used, for example, a polyorganosiloxane obtained by: causing asiloxane having a cyclic structure such as octamethylcyclotetrasiloxaneand a disiloxane such as tetramethyldisiloxane to react with each otherto produce a linear dimethylsiloxane; and causing a hydrogen atom at aterminal of the dimethylsiloxane to react with a phenolic compound suchas 2-allylphenol or eugenol in the presence of a platinumchloride-alcoholate complex as a catalyst (see Patent Documents 4 to 6).

CITATION LIST Patent Document Patent Document 1: JP 2662310 B2 PatentDocument 2: JP 2011-21127 A Patent Document 3: JP 2012-246430 A PatentDocument 4: JP 2011-122048 A Patent Document 5: JP 2012-46717 A PatentDocument 6: JP 11-217290 A SUMMARY OF INVENTION Technical Problem

When a polycarbonate-polyorganosiloxane copolymer is produced by aninterfacial polymerization method, in a purifying step, a reactionmixture needs to be subjected to oil-water separation into an organicphase formed of an organic solvent (such as methylene chloride)containing the polycarbonate-polyorganosiloxane copolymer and an aqueousphase containing unreacted bisphenol A and an amine compound used in apolymerization catalyst. In addition, even after alkali washing, acidwashing, and pure water washing for removing impurities from theseparated organic phase have been performed, the organic phase and theaqueous phase need to be subjected to oil-water separation from eachother.

However, the oil-water separation rate has heretofore taken time andhence has been adversely affecting the productivity of the copolymer.

Therefore, an object of the present invention is to provide a method ofproducing the following polyorganosiloxane. When the polyorganosiloxaneis used as a raw material for a polycarbonate-polyorganosiloxanecopolymer, an oil-water separation rate in the step of purifying thepolycarbonate-polyorganosiloxane copolymer is high.

Solution to Problem

The inventors of the present invention have made extensiveinvestigations, and as a result, have found that platinum used as acatalyst at the time of the production of a polyorganosiloxane remainsin the polyorganosiloxane, which results in an adverse effect onseparation between an organic phase and an aqueous phase upon productionof a polycarbonate-polyorganosiloxane copolymer through the use of thepolyorganosiloxane as a raw material by an interfacial polymerizationmethod. The present invention has been made on the basis of suchfinding.

That is, the present invention relates to a method of producing apolyorganosiloxane, a polyorganosiloxane, and apolycarbonate-polyorganosiloxane copolymer according to the followingitems 1 to 10.

1. A method of producing a polyorganosiloxane, including bringing apolyorganosiloxane produced by using a transition metal-based catalystinto contact with an adsorbent having an average pore diameter of 1,000Å or less.2. The method of producing a polyorganosiloxane according to the item 1,wherein the adsorbent includes a porous adsorbent.3. The method of producing a polyorganosiloxane according to the item 1or 2, wherein the adsorbent includes at least one selected from thegroup consisting of activated clay, acid clay, activated carbon, asynthetic zeolite, a natural zeolite, activated alumina, silica, and asilica-magnesia-based adsorbent.4. The method of producing a polyorganosiloxane according to any one ofthe items 1 to 3, wherein the polyorganosiloxane is represented by thefollowing general formula (1-1):

wherein R¹ to R⁴ each independently represent a hydrogen atom, a halogenatom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, Yrepresents a single bond, or an organic residue containing an aliphaticor aromatic moiety, the organic residue being bonded to Si and O or toSi and Z, n represents an average number of repetitions, m represents 0or 1, Z each independently represent a halogen, —R⁵OH, —R⁵COOH, —R⁵NH₂,—R⁵NHR⁶, —COOH, or —SH, R⁵ represents a linear, branched, or cyclicalkylene group, an aryl-substituted alkylene group, an aryl-substitutedalkylene group that may have an alkoxy group on a ring thereof, or anarylene group, and R⁶ represents an alkyl group, an alkenyl group, anaryl group, or an aralkyl group.5. The method of producing a polyorganosiloxane according to the item 4,wherein R¹ to R⁴ each independently represent a hydrogen atom, an alkylgroup having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbonatoms, or an aryl group having 6 to 12 carbon atoms, and Z eachindependently represent —R⁵OH, —R⁵COOH, —R⁵NH₂, —R⁵NHR⁶, —COOH, or —SH.6. The method of producing a polyorganosiloxane according to any one ofthe items 1 to 5, wherein the polyorganosiloxane is represented by thefollowing general formula (1-2) or (1-4):

wherein R¹ to R⁴ each independently represent a hydrogen atom, a halogenatom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, nrepresents an average number of repetitions, and a represents a positiveinteger.7. The method of producing a polyorganosiloxane according to any one ofthe items 4 to 6, wherein R¹ to R⁴ each represent a methyl group.8. A polyorganosiloxane produced by the method of any one of the items 1to 7, the polyorganosiloxane having a platinum content of 1 ppm by massor less.9. A polycarbonate-polyorganosiloxane copolymer produced by using thepolyorganosiloxane of the item 8.10. The polycarbonate-polyorganosiloxane copolymer according to the item9, wherein the polycarbonate-polyorganosiloxane copolymer includes apolyorganosiloxane moiety as a repeating unit having a structurerepresented by the following general formula (I) and a polycarbonatemoiety as a repeating unit having a structure represented by thefollowing general formula (II):

wherein R¹¹ to R¹⁴ each independently represent a hydrogen atom, ahalogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy grouphaving 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbonatoms, Y¹ represents a single bond, or an organic residue containing analiphatic or aromatic moiety, n1 represents an average number ofrepetitions, R²¹ and R²² each independently represent a halogen atom, analkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6carbon atoms, X represents a single bond, an alkylene group having 1 to8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, acycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene grouphaving 5 to 15 carbon atoms, a fluorenediyl group, an arylalkylene grouphaving 7 to 15 carbon atoms, an arylalkylidene group having 7 to 15carbon atoms, —S—, —SO—, —SO₂—, —O—, or —CO—, and b and c eachindependently represent an integer of 0 to 4.

Advantageous Effects of Invention

According to the method of the present invention, a polyorganosiloxanewhose transition metal content, especially platinum content is small canbe efficiently produced. When the polyorganosiloxane obtained by thepresent invention is used, an oil-water separation rate in the step ofpurifying a polycarbonate-polyorganosiloxane copolymer is high, andhence the polycarbonate-polyorganosiloxane copolymer can be efficientlyproduced.

DESCRIPTION OF EMBODIMENTS

A method of producing a polyorganosiloxane of the present inventionincludes bringing a polyorganosiloxane produced by using a transitionmetal-based catalyst (hereinafter sometimes referred to as “crudepolyorganosiloxane”) into contact with an adsorbent having an averagepore diameter of 1,000 Å or less.

<Polyorganosiloxane>

In the present invention, the polyorganosiloxane preferably has arepeating unit represented by the following general formula (1).

wherein, R¹ and R² each independently represent a hydrogen atom, ahalogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy grouphaving 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbonatoms.

Examples of the halogen atom represented by R¹ or R² include a fluorineatom, a chlorine atom, a bromine atom, and an iodine atom. Examples ofthe alkyl group represented by R¹ or R² include a methyl group, an ethylgroup, a n-propyl group, an isopropyl group, various butyl groups(“various” means that a linear group and any branched group areincluded, and the same applies hereinafter), various pentyl groups, andvarious hexyl groups. An example of the alkoxy group represented by R¹or R² is an alkoxy group whose alkyl group moiety is the alkyl groupdescribed above. Examples of the aryl group represented by R¹ or R²include a phenyl group and a naphthyl group.

It should be noted that R¹ and R² each preferably represent a hydrogenatom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, andeach more preferably represent a methyl group.

The polyorganosiloxane is preferably represented by the followinggeneral formula (1-1).

wherein R¹ to R⁴ each independently represent a hydrogen atom, a halogenatom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, Yrepresents a single bond, or an organic residue containing an aliphaticor aromatic moiety, the organic residue being bonded to Si and O or toSi and Z, n represents an average number of repetitions, m represents 0or 1, Z each independently represent a halogen, —R⁵OH, —R⁵COOH, —R⁵NH₂,—R⁵NHR⁶, —COOH, or —SH, R⁵ represents a linear, branched, or cyclicalkylene group, an aryl-substituted alkylene group, an aryl-substitutedalkylene group that may have an alkoxy group on a ring thereof, or anarylene group, and R⁶ represents an alkyl group, an alkenyl group, anaryl group, or an aralkyl group.

R¹ and R² are as described above, and R³ and R⁴ are the same as R¹ andR². R¹ to R⁴ each preferably represent a hydrogen atom, an alkyl grouphaving 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms,or an aryl group having 6 to 12 carbon atoms, and each more preferablyrepresent a methyl group.

Y represents a single bond, or an organic residue containing analiphatic or aromatic moiety, the organic residue being bonded to Si andO or to Si and Z.

n represents an average number of repetitions and is preferably 10 to1,000. It should be noted that a value for the average number ofrepetitions n is a value calculated by nuclear magnetic resonance (NMR)measurement.

Z preferably represents —R⁵OH, —R⁵COOH, —R⁵NH₂, —R⁵NHR⁶, —COOH, or —SH.As in the foregoing, the R⁵ represents a linear, branched, or cyclicalkylene group, an aryl-substituted alkylene group, an aryl-substitutedalkylene group that may have an alkoxy group on a ring thereof, or anarylene group, and R⁶ represents an alkyl group, an alkenyl group, anaryl group, or an aralkyl group. Z preferably represents a residue of aphenol-based compound having an alkyl group, and more preferablyrepresents an organic residue derived from allylphenol or an organicresidue derived from eugenol.

Examples of the polyorganosiloxane represented by the general formula(1-1) include compounds represented by the following general formulae(1-2) to (1-12).

In the general formulae (1-2) to (1-12), R¹ to R⁴, R⁶, and n are asdescribed above, and preferred ones thereof are also the same as thosedescribed above. In addition, a represents a positive integer andtypically represents an integer of 1 to 6.

Among them, a phenol-modified polyorganosiloxane represented by thegeneral formula (1-2) is preferred from the viewpoint of the ease ofpolymerization upon production of a polycarbonate-polyorganosiloxanecopolymer. From the viewpoint of the ease of availability,α,ω-bis[3-(o-hydroxyphenyl)propyl]polydimethylsiloxane as one kind ofthe compounds each represented by the general formula (1-3) orα,ω-bis[3-(4-hydroxy-3-methoxyphenyl)propyl]polydimethylsiloxane as onekind of the compounds each represented by the general formula (1-4) ispreferred.

A method of producing the crude polyorganosiloxane to be used in thepresent invention is not particularly limited. According to, forexample, a method described in JP 11-217390 A, the crudepolyorganosiloxane can be obtained by: causing cyclotrisiloxane anddisiloxane to react with each other in the presence of an acid catalystto synthesize α,ω-dihydrogen organopentasiloxane; and then subjectingthe α,ω-dihydrogen organopentasiloxane to an addition reaction with aphenolic compound (such as 2-allylphenol, 4-allylphenol, eugenol, or2-propenylphenol) or the like in the presence of a catalyst for ahydrosilylation reaction. According to a method described in JP 2662310B2, the crude polyorganosiloxane can be obtained by: causingoctamethylcyclotetrasiloxane and tetramethyldisiloxane to react witheach other in the presence of sulfuric acid (acid catalyst); andsubjecting the resultant α,ω-dihydrogen organopolysiloxane to anaddition reaction with a phenolic compound in the presence of thecatalyst for a hydrosilylation reaction in the same manner as in theforegoing. It should be noted that the chain length n of theα,ω-dihydrogen organopolysiloxane can be appropriately adjusteddepending on a polymerization condition therefor before its use, or acommercially available α,ω-dihydrogen organopolysiloxane may be used.

Examples of the catalyst for a hydrosilylation reaction includetransition metal-based catalysts. Among them, a platinum-based catalystis preferably used in terms of a reaction rate and selectivity. Specificexamples of the platinum-based catalyst include chloroplatinic acid, asolution of chloroplatinic acid in an alcohol, an olefin complex ofplatinum, a complex of platinum and a vinyl group-containing siloxane,platinum-supported silica, and platinum-supported activated carbon.

<Adsorbent>

In the method of the present invention, the adsorbent is caused toadsorb and remove a transition metal derived from the transitionmetal-based catalyst used as the catalyst for a hydrosilylation reactionin the crude polyorganosiloxane by bringing the crude polyorganosiloxaneinto contact with the adsorbent.

The adsorbent to be used in the present invention has an average porediameter of 1,000 Å or less. When the average pore diameter is 1,000 Åor less, the transition metal in the crude polyorganosiloxane can beefficiently removed. From such viewpoint, the average pore diameter ofthe adsorbent is preferably 500 Å or less, more preferably 200 Δ orless, still more preferably 150 Å or less, still furthermore preferably100 Å or less. In addition, from the same viewpoint, the adsorbent ispreferably a porous adsorbent.

It should be noted that the average pore diameter of the adsorbent ismeasured with an automatic gas adsorption measuring device, and isspecifically measured by a method described in Examples.

The adsorbent is not particularly limited as long as the adsorbent hasthe above-mentioned average pore diameter. For example, there may beused activated clay, acid clay, activated carbon, a synthetic zeolite, anatural zeolite, activated alumina, silica, a silica-magnesia-basedadsorbent, diatomaceous earth, and cellulose. The adsorbent ispreferably at least one selected from the group consisting of activatedclay, acid clay, activated carbon, a synthetic zeolite, a naturalzeolite, activated alumina, silica, and a silica-magnesia-basedadsorbent.

After the adsorbent has been caused to adsorb the transition metal inthe crude polyorganosiloxane, the adsorbent can be separated from thepolyorganosiloxane by arbitrary separating means. Examples of the meansfor separating the adsorbent from the polyorganosiloxane include afilter and centrifugation. When the filter is used, a filter such as amembrane filter, a sintered metal filter, or a glass fiber filter can beused. Among them, the membrane filter is particularly preferably used.

The average particle diameter of the adsorbent is typically 1 μm to 4mm, preferably 1 μm to 100 μm from the viewpoint of separating theadsorbent from the polyorganosiloxane after the adsorption of thetransition metal.

In the present invention, the amount of the adsorbent used is notparticularly limited. However, the amount of the porous adsorbent usedfalls within the range of preferably 1 part by mass to 30 parts by mass,more preferably 2 parts by mass to 20 parts by mass with respect to 100parts by mass of the crude polyorganosiloxane.

It should be noted that when the crude polyorganosiloxane to be treatedhas so high a molecular weight and the crude polyorganosiloxane is notin a liquid state, the polyorganosiloxane may be heated to such atemperature as to be in a liquid state upon performance of theadsorption with the adsorbent and the separation of the adsorbent.Alternatively, the polyorganosiloxane is dissolved in a solvent such asmethylene chloride or hexane, and then the adsorption and the separationmay be performed.

A polyorganosiloxane produced by the method of the present invention hasa transition metal content, especially a platinum content of 1 ppm bymass or less, preferably 0.5 ppm by mass or less, more preferably 0.2ppm by mass or less. When the platinum content in the polyorganosiloxaneis 1 ppm by mass or less, an oil-water separation rate in the step ofpurifying a polycarbonate-polyorganosiloxane copolymer upon productionof the polycarbonate-polyorganosiloxane copolymer through the use of thepolyorganosiloxane can be increased. In addition, when the platinumcontent in the polyorganosiloxane is 1 ppm by mass or less, the hue ofthe polyorganosiloxane improves. Here, a situation where the hue of thepolyorganosiloxane improves is assumed to mean that the oxidativedeterioration of the polyorganosiloxane has been reduced. In otherwords, a situation where the hue of the polyorganosiloxane is bad isassumed to mean that the oxidative deterioration of thepolyorganosiloxane is progressing. In view of the above, for example,when a composition is produced by using the polyorganosiloxane producedby the method of the present invention as an additive (such as a releaseagent) and a molded article is produced from the composition, animproving effect on the hue of the molded article is expected. In otherwords, in the case where the polyorganosiloxane of the present inventionis used, the hue of the molded article is expected to improve ascompared to the case where a polyorganosiloxane having a bad hue is usedas an additive.

The transition metal content, especially the platinum content in thepolyorganosiloxane in the present invention is measured with an ICPemission analyzer and is specifically measured by a method described inExamples.

<Polycarbonate-Polyorganosiloxane Copolymer>

The polyorganosiloxane produced by the method of the present inventioncan be suitably used in the production of apolycarbonate-polyorganosiloxane copolymer (hereinafter sometimesabbreviated as “PC-POS copolymer”). A known production method such as aninterfacial polymerization method (phosgene method), a pyridine method,or an ester exchange method can be employed as a method of producing thePC-POS copolymer. Particularly in the case of the interfacialpolymerization method, the step of separating an organic phasecontaining the PC-POS copolymer and an aqueous phase containing anunreacted substance, a catalyst residue, or the like becomes easy, andhence the separation of the organic phase containing the PC-POScopolymer and the aqueous phase in each washing step based on alkaliwashing, acid washing, or pure water washing becomes easy. Accordingly,the PC-POS copolymer is efficiently obtained.

In addition, the PC-POS copolymer obtained by using thepolyorganosiloxane of the present invention is of high quality becausethe copolymer has a small amount of a catalyst residue derived from theplatinum-based catalyst in the copolymer. The PC-POS copolymer of thepresent invention has a platinum content of 0.4 ppm by mass or less,preferably 0.2 ppm by mass or less, more preferably 0.08 ppm by mass orless, still more preferably 0.06 ppm by mass or less. It should be notedthat the platinum content in the PC-POS copolymer is measured with anICP emission analyzer as in the measurement of the platinum content inthe polyorganosiloxane.

The PC-POS copolymer of the present invention preferably includes apolyorganosiloxane moiety as a repeating unit having a structurerepresented by the following general formula (I) and a polycarbonatemoiety as a repeating unit having a structure represented by thefollowing general formula (II).

wherein R¹¹ to R¹⁴ each independently represent a hydrogen atom, ahalogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy grouphaving 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbonatoms, Y¹ represents a single bond, or an organic residue containing analiphatic or aromatic moiety, n1 represents an average number ofrepetitions, R²¹ and R²² each independently represent a halogen atom, analkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6carbon atoms, X represents a single bond, an alkylene group having 1 to8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, acycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene grouphaving 5 to 15 carbon atoms, a fluorenediyl group, an arylalkylene grouphaving 7 to 15 carbon atoms, an arylalkylidene group having 7 to 15carbon atoms, —S—, —SO—, —SO₂—, —O—, or —CO—, and b and c eachindependently represent an integer of 0 to 4.

In the general formula (I), R¹¹ to R¹⁴, Y¹, and n1 are the same as R¹ toR⁴, Y, and n in the general formula (1-1), and preferred ones thereofare also the same as those in the above.

A method of producing the PC-POS copolymer is not particularly limitedand the copolymer can be produced with reference to a known method ofproducing a PC-POS copolymer such as a method described in JP2010-241943 A.

Specifically, the PC-POS copolymer can be produced by: dissolving anaromatic polycarbonate oligomer produced in advance and thepolyorganosiloxane of the present invention in a water-insoluble organicsolvent (such as methylene chloride); adding an aqueous solution of adihydric phenol-based compound (such as bisphenol A) in an alkalinecompound (such as aqueous sodium hydroxide) to the solution; andsubjecting the mixture to an interfacial polycondensation reactionthrough the use of a tertiary amine (such as triethylamine) or aquaternary ammonium salt (such as trimethylbenzylammonium chloride) as apolymerization catalyst in the presence of a terminal stopper (amonohydric phenol such as p-t-butylphenol). In addition, the PC-POScopolymer can be produced by copolymerizing a polyorganosiloxane, adihydric phenol, and phosgene, a carbonate, or a chloroformate.

The polyorganosiloxane represented by the general formula (1-1) ispreferably used as the polyorganosiloxane. It should be noted that thecontent of the repeating unit containing a structure represented by thegeneral formula (I) can be adjusted by, for example, adjusting the usageamount of the polyorganosiloxane represented by the general formula(1-1).

The polycarbonate oligomer can be produced through a reaction of adihydric phenol and a carbonate precursor such as phosgene in an organicsolvent such as methylene chloride, chlorobenzene, or chloroform. Whenthe polycarbonate oligomer is produced by using a transesterificationmethod, the oligomer can also be produced through a reaction of adihydric phenol and a carbonate precursor such as diphenyl carbonate.

A dihydric phenol represented by the following general formula (2) ispreferably used as the dihydric phenol.

In the formula, R₂₁, R₂₂, X, b, and c are as described above.

Examples of the dihydric phenol represented by the general formula (2)include bis(hydroxyphenyl)alkane dihydric phenols such as2,2-bis(4-hydroxyphenyl)propane [bisphenol A],bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, and2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 4,4′-dihydroxydiphenyl, abis(4-hydroxyphenyl)cycloalkane, bis(4-hydroxyphenyl) oxide,bis(4-hydroxyphenyl) sulfide, bis(4-hydroxyphenyl) sulfone,bis(4-hydroxyphenyl) sulfoxide, and bis(4-hydroxyphenyl) ketone.

Among them, bis(hydroxyphenyl)alkane-based dihydric phenols arepreferred, and bisphenol A is more preferred. When bisphenol A is usedas the dihydric phenol, the PC-POS copolymer in which X represents anisopropylidene group and a relationship of b=c=0 is satisfied in thegeneral formula (II) is obtained.

Examples of the dihydric phenol other than bisphenol A include abis(hydroxyaryl)alkane, a bis(hydroxyaryl)cycloalkane, a dihydroxyarylether, a dihydroxydiaryl sulfide, a dihydroxydiaryl sulfoxide, adihydroxydiaryl sulfone, a dihydroxydiphenyl, a dihydroxydiarylfluorene,and a dihydroxydiaryladamantane. One of those dihydric phenols may beused alone, or two or more thereof may be used as a mixture.

Examples of the bis(hydroxyaryl)alkane includebis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane,2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane,bis(4-hydroxyphenyl)phenylmethane, bis(4-hydroxyphenyl)diphenylmethane,2,2-bis(4-hydroxy-3-methylphenyl)propane,bis(4-hydroxyphenyl)naphthylmethane,1,1-bis(4-hydroxy-t-butylphenyl)propane,2,2-bis(4-hydroxy-3-bromophenyl)propane,2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane,2,2-bis(4-hydroxy-3-chlorophenyl)propane,2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, and2,2-bis(4-hydroxy-3,5-dibromophenyl)propane.

Examples of the bis(hydroxyaryl)cycloalkane include1,1-bis(4-hydroxyphenyl)cyclopentane,1,1-bis(4-hydroxyphenyl)cyclohexane,1,1-bis(4-hydroxyphenyl)-3,5,5-trimethylcyclohexane,2,2-bis(4-hydroxyphenyl)norbornane, and1,1-bis(4-hydroxyphenyl)cyclododecane. Examples of the dihydroxyarylether include 4,4′-dihydroxyphenyl ether and4,4′-dihydroxy-3,3′-dimethylphenyl ether.

Examples of the dihydroxydiaryl sulfide include 4,4′-dihydroxydiphenylsulfide and 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfide. Examples ofthe dihydroxydiaryl sulfoxide include 4,4′-dihydroxydiphenyl sulfoxideand 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfoxide. Examples of thedihydroxydiaryl sulfone include 4,4′-dihydroxydiphenyl sulfone and4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfone.

An example of the dihydroxydiphenyl is 4,4′-dihydroxydiphenyl. Examplesof the dihydroxydiarylfluorene include 9,9-bis(4-hydroxyphenyl)fluoreneand 9,9-bis(4-hydroxy-3-methylphenyl) fluorene. Examples of thedihydroxydiaryladamantane include 1,3-bis(4-hydroxyphenyl)adamantane,2,2-bis(4-hydroxyphenyl)adamantane, and1,3-bis(4-hydroxyphenyl)-5,7-dimethyladamantane.

Examples of the dihydric phenol other than the above-mentioned dihydricphenol include 4,4′-[1,3-phenylenebis(1-methylethylidene)]bisphenol,10,10-bis(4-hydroxyphenyl)-9-anthrone, and1,5-bis(4-hydroxyphenylthio)-2,3-dioxapentane.

Further, the PC-POS copolymer can be produced by copolymerizing thedihydric phenol represented by the general formula (2), apolyorganosiloxane represented by the following general formula (3), andphosgene, a carbonate ester, or a chloroformate. Here, thepolyorganosiloxane represented by the following general formula (3) is aproduct of a reaction between the polyorganosiloxane represented by thegeneral formula (1-1) and a diisocyanate compound.

In the general formula (3), R¹ to R⁴, n, m, Y, and Z are as defined inthe above, and preferred ones thereof are also the same as those in theabove.

Z¹ represents a divalent group derived from Z in the polyorganosiloxanerepresented by the general formula (1-1) after the reaction of the Zwith a —NCO group of the diisocyanate compound.

β represents a divalent group derived from the diisocyanate compound, ora divalent group derived from a dicarboxylic acid or a halide of thedicarboxylic acid, and examples thereof include divalent groups eachrepresented by anyone of the following general formulae (3-1) to (3-5).

In order to control the molecular weight of the PC-POS copolymer to beobtained, a terminal stopper can be used. Examples of the terminalstopper may include monohydric phenols such as phenol, p-cresol,p-tert-butylphenol, p-tert-octylphenol, p-cumylphenol, p-nonylphenol,and p-tert-amylphenol. One of those monohydric phenols may be usedalone, or two or more thereof may be used in combination.

In the PC-POS copolymer of the present invention, n (a degree ofpolymerization) representing the chain length of the polyorganosiloxanerepresented by the general formula (1-1) is typically about 10 to 1,000,and is preferably 30 to 600, more preferably 40 to 300, still morepreferably 40 to 200 from the viewpoints of an improvement in impactstrength of the copolymer, workability, and an excellent flameretardancy. When n is 10 or more, an improving effect on the impactstrength becomes sufficient, and when n is 1,000 or less, handleabilityupon production of the PC-POS copolymer becomes satisfactory, whicheliminates such a risk that the workability is impaired.

The PC-POS copolymer of the present invention can be produced byappropriately using, for example, a molecular weight modifier so thatits viscosity-average molecular weight may be a molecular weightintended for an application or product in which the copolymer is used.The copolymer is produced so as to have a viscosity-average molecularweight in the range of typically about 14,000 to 23,000, preferablyabout 15,000 to 22,000. When the viscosity-average molecular weight is14,000 or more, the rigidity and impact strength of a molded bodyobtained by molding the copolymer become sufficient, and when themolecular weight is 23,000 or less, the viscosity of the PC-POScopolymer does not become excessively large and hence the productivityupon its production becomes satisfactory. In addition, there is no riskin that it becomes difficult to mold the copolymer into a thin body.

It should be noted that the viscosity-average molecular weight (Mv) is avalue calculated from Schnell's equation ([η]=1.23×10⁻⁵×Mv^(0.83)) bymeasuring the limiting viscosity [η] of a methylene chloride solution at20° C.

After the interfacial polycondensation reaction, the resultant isappropriately left at rest to be separated into an aqueous phase and awater-insoluble organic solvent phase [separating step], thewater-insoluble organic solvent phase is washed (preferably washed witha basic aqueous solution, an acidic aqueous solution, and water in thestated order) [washing step], and the resultant organic phase isconcentrated [concentrating step], pulverized [pulverizing step], anddried [drying step]. Thus, the PC-POS copolymer can be obtained.According to the present invention, oil-water separation rates in theseparating step and the washing step are high, and hence the PC-POScopolymer can be efficiently produced.

EXAMPLES

The present invention is more specifically described by way of Examples.However, the present invention is by no means limited by these Examples.

It should be noted that in each of Examples, characteristic values andevaluation results were determined in the following manner.

(1) Average Pore Diameter of Adsorbent

A filtering medium adsorbent was subjected to a vacuum evacuationtreatment at 200° C. for 3 hours, and its average pore diameter wasmeasured with a pore size analyzer (“AUTOSORB-3” manufactured byQuantachrome Instruments) by a constant volume method (nitrogenadsorption).

(2) Platinum Content

A platinum content in a sample was measured with an ICP emissionanalyzer (manufactured by Hitachi High-Tech Science Corporation, tradename: “SPS5100”) under the measurement conditions of a calibration curvemethod.

(3) Platinum Removal Ratio

The removal ratio of platinum from a PDMS was calculated by thefollowing method.

Removal ratio (%)={1−[platinum content (ppm by mass) in PDMS afterpurification]/[platinum content (ppm by mass) in PDMS beforepurification]}×100

In particular, the platinum content in the PDMS after the purificationrepresents the platinum content in the PDMS after the purification of acrude polyorganosiloxane with an adsorbent in each of Examples 1 to 6,and represents the platinum content in the PDMS after the purificationof the crude polyorganosiloxane with a filter made of polypropylene inComparative Example 2. The platinum content in the PDMS before thepurification represents the platinum content in the PDMS measured inComparative Example 1.

(4) Hue Evaluation (APHA)

A hue was visually evaluated by using an APHA standard color.

(5) Viscosity-average Molecular Weight ofPolycarbonate-polyorganosiloxane Copolymer

A viscosity-average molecular weight (Mv) was calculated from thefollowing equation by using a limiting viscosity [η] determined throughthe measurement of the viscosity of a methylene chloride solution at 20°C. with an Ubbelohde-type viscometer.

[η]=1.23×10⁻⁵Mv^(0.83)

(6) Water Content in Organic Phase after Oil-Water Separation

A water content in an organic phase after oil-water separation wasmeasured by titrating water using a water vaporizer (“Model VA-100”manufactured by Mitsubishi Chemical Corporation) and a tracewater-measuring apparatus (“Model CA-100” manufactured by MitsubishiChemical Corporation) according to Karl Fischer titration. Themeasurement was performed under the following measurement conditions:the flow rate of a nitrogen gas in the water vaporizer was 250 ml/minand the temperature of the heating furnace of the water vaporizer was230° C.

Example 1 (1) Production of Crude Polyorganosiloxane

594 g (2 mol) of octamethylcyclotetrasiloxane, 30.0 g (0.2 mol) of 1, 1,3, 3-tetramethyldisiloxane, and 35 g of 86 mass % sulfuric acid weremixed, and the mixture was stirred at room temperature for 17 hours. Anoil phase was separated from the mixture, 25 g of sodium hydrogencarbonate was added to the phase, and the resultant mixture was stirredfor 1 hour to be neutralized. After the neutralized product had beenfiltered, volatile matter mainly formed of a low-molecular weightpolyorganosiloxane was removed by distilling the filtrate at 150° C. ina vacuum of 400 Pa.

309 g of the oil obtained in the above was added at 90° C. to a solutionprepared by dissolving 148 g (1.1 mol) of 2-allylphenol and 0.0044 g ofchloroplatinic acid hexahydrate in 1 mL of an isopropyl alcoholsolution. The mixture was stirred for 3 hours while its temperature waskept at 90° C. to 115° C.

The product thus obtained was dissolved in 10 L of methylene chloride.After that, the solution was washed with 1.5 L of 0.3 mol/L aqueous NaOHtwice, washed with 1.5 L of 2 mass % phosphoric acid for neutralization,and further washed with water once. Methylene chloride was removed byconcentration at 30° C. to 40° C. under reduced pressure, and methylenechloride was further removed under reduced pressure at 60° C. Thus, a2-allylphenol terminal-modified PDMS (crude PDMS) was obtained.

The structure and composition of the resultant crude PDMS were analyzedby ¹H-NMR. As a result, the number of repetitions of the dimethylsiloxyunit of the resultant 2-allylphenol terminal-modified PDMS was 40. Inaddition, a platinum content in the crude PDMS was 2.0 ppm by mass.

(2) Purification of Polyorganosiloxane (Production of PDMS-1)

20 g of methylene chloride and 20 g of the 2-allylphenolterminal-modified PDMS obtained in the above were loaded into a 100-mLglass vessel, and the 2-allylphenol terminal-modified PDMS was dissolvedin methylene chloride. Next, 1 g of activated clay (manufactured byMizusawa Industrial Chemicals, Ltd., trade name: “GALLEON EARTH V2”,average pore diameter: 63 Å) was added as an adsorbent to the solution,and the mixture was stirred at 17° C. for 3 hours. The activated clayused as the adsorbent was suction-filtered with a membrane filter(manufactured by ADVANTEC, filter paper made of polytetrafluoroethylene,pore diameter: 0.2 μm). Thus, a filtrate was obtained. Methylenechloride was removed by concentrating the filtrate, and then the residuewas dried under vacuum to provide a 2-allylphenol terminal-modified PDMS(PDMS-1). A platinum content in the 2-allylphenol terminal-modified PDMSwas 0.1 ppm by mass. A platinum removal ratio by the purification was 95mass %. The APHA of the purified polyorganosiloxane was 25. The resultsare shown in Table 1.

Examples 2 to 6

Polyorganosiloxanes (PDMS-2 to PDMS-6) were each produced by using thecrude PDMS produced in the section (1) of Example 1 (platinum content:2.0 ppm by mass) in the same manner as in Example 1 except that anadsorbent shown in Table 1 was used as an adsorbent instead of theactivated clay, and the polyorganosiloxanes were subjected to similarmeasurements. The results are shown in Table 1.

It should be noted that the adsorbents used in Examples are as describedbelow.

Acid clay (manufactured by Mizusawa Industrial Chemicals, Ltd., tradename: “MIZUKA ACE #20”, average pore diameter: 108 Å)

Activated carbon (manufactured by Wako Pure Chemical Industries, Ltd.,average pore diameter: 40 Å)

Silica-magnesia (manufactured by Mizusawa Industrial Chemicals, Ltd.,trade name: “MIZUKALIFE P-l”, average pore diameter: 70 Å)

Synthetic zeolite (manufactured by Mizusawa Industrial Chemicals, Ltd.,trade name: “MIZUKASIEVES EX-122”, average pore diameter: 19 Å)

Activated alumina (manufactured by Mizusawa Industrial Chemicals, Ltd.,trade name: “ACTIVATED ALUMINA GP-20”, average pore diameter: 111 Å)

Comparative Example 1

A polyorganosiloxane (PDMS-7) was produced by using the crude PDMSproduced in the section (1) of Example 1 (platinum content: 2.0 ppm bymass) in the same manner as in Example 1 except that no adsorbent wasused, and the polyorganosiloxane was subjected to similar measurements.The results are shown in Table 1.

Comparative Example 2

A tubular filter made of polypropylene having an inner diameter of 8.5cm and a length of 12.5 cm (“Model BFP-410-1” manufactured by TakiEngineering Co., Ltd.) was set in a cylindrical glass vessel having aninner diameter of 10 cm and a height of 18 cm. 20 g of the crude PDMSproduced in the section (1) of Example 1 (platinum content: 2.0 ppm bymass) was flowed into the filter to provide a filtrate as apolyorganosiloxane (PDMS-8). After that, similar measurements wereperformed. The results are shown in Table 1.

TABLE 1 Example Comparative Example 1 2 3 4 5 6 1 2 PDMS PDMS-1 PDMS-2PDMS-3 PDMS-4 PDMS-5 PDMS-6 PDMS-7 PDMS-8 Chain length (*1) 40 40 40 4040 40 40 40 Adsorbent Activated Acid Activated Silica- SyntheticActivated None None (*2) clay clay carbon magnesia zeolite aluminaAverage pore diameter of adsorbent (Å) 63 108 40 70 19 111 — — (*2) Ptcontent (ppm by mass) 0.1 0.1 0.1 0.1 0.2 0.3 2.0 2.0 Pt removal ratio(mass %) 95 95 95 95 90 85 0 0 APHA of PDMS 25 25 25 25 60 60 300 300(*1): The number of repetitions of a dimethylsiloxy unit in a PDMS (*2):A tubular filter made of polypropylene (having an average pore diameterof 10,000 Å) was used.

The polyorganosiloxane (PDMS-7) of Comparative Example 1 which did notbe treated with any adsorbent was poor in hue. In Comparative Example 2where the filter made of polypropylene having an average pore diameterof 10,000 Å was used, platinum could not be removed and the resultantpolyorganosiloxane (PDMS-8) was poor in hue as in Comparative Example 1.

In contrast, in Examples 1 to 6 where the adsorbents each having anaverage pore diameter of 1,000 Å or less were used, platinum was able tobe effectively removed, and the resultant polyorganosiloxanes (PDMS-1 toPDMS-6) each had a platinum content of 1 ppm by mass or less and asatisfactory hue.

Production Example 1 Production of Polycarbonate Oligomer

To 5.6 mass aqueous sodium hydroxide, 2,000 ppm by mass % of sodiumdithionite with respect to bisphenol A (hereinafter referred to as“BPA”) to be dissolved later was added. BPA was dissolved in thesolution so that the concentration of BPA became 13.5 mass %. Thus, asolution of BPA in aqueous sodium hydroxide was prepared.

The solution of BPA in aqueous sodium hydroxide, methylene chloride, andphosgene were continuously passed through a tubular reactor having aninner diameter of 6 mm and a tube length of 30 m at flow rates of 40L/h, 15 L/h, and 4.0 kg/h, respectively. The tubular reactor had ajacket portion and the temperature of a reaction liquid was kept at 40°C. or less by passing cooling water through the jacket.

The reaction liquid which had exited the tubular reactor wascontinuously introduced into a baffled vessel-type reactor having aninternal volume of 40 L provided with a sweptback blade, and then thesolution of BPA in aqueous sodium hydroxide, 25 mass aqueous sodiumhydroxide, water, and a 1 mass % aqueous solution of triethylamine werefurther added to the reactor at flow rates of 2.8 L/h, 0.07 L/h, 17 L/h,and 0.64 L/h, respectively, to thereby perform a reaction. The reactionliquid flowing out of the vessel-type reactor was continuously takenout, and then an aqueous phase was separated and removed by leaving theliquid at rest, followed by the collection of a methylene chloridephase. Thus, a polycarbonate oligomer solution was obtained.

The polycarbonate oligomer solution had a polycarbonate oligomerconcentration of 318 g/L.

A chloroformate group concentration in the polycarbonate oligomer was0.75 mol/L. It should be noted that the chloroformate groupconcentration was determined from ¹H-NMR analysis.

The polycarbonate oligomer had a weight-average molecular weight (Mw) of1,190.

The weight-average molecular weight (Mw) of the polycarbonate oligomerwas measured as a molecular weight by using the polystyrene calibrationcurve according to GPC using tetrahydrofuran as a developing solventunder the following conditions.

Columns: “TOSOH TSK-GEL MULTIPORE HXL-M” manufactured by TosohCorporation (2 columns)+“Shodex KF801” manufactured by Showa Denko K.K.(1 column)

Temperature: 40° C.

Flow rate: 1.0 ml/min

Detector: RI Example 7 (1) Production ofPolycarbonate-Polyorganosiloxane Copolymer

377 mL of the polycarbonate oligomer solution produced in ProductionExample 1 described above, 223 mL of methylene chloride, 10.2 g of the2-allylphenol terminal-modified PDMS having a number of repetitions ofthe dimethylsiloxy unit of 40 (PDMS-1 produced in Example 1), and 138 μLof triethylamine were loaded into a 1-L tank reactor mounted with aglass reactor having an inner diameter of 10.5 cm and a height of 15.5cm, 4 baffle boards each having a width of 1.5 cm and a height of 13 cm,and a T-shaped stirring blade having a lateral width of 9 cm and avertical width of 1.5 cm. 28.26 g of 6.4 mass % aqueous sodium hydroxidewas added to the mixture under stirring, and a reaction between thepolycarbonate oligomer and the 2-allylphenol terminal-modified PDMS wasperformed for 10 minutes. A solution of p-t-butylphenol (PTBP) inmethylene chloride (prepared by dissolving 3.44 g of PTBP in 24 mL ofmethylene chloride) and a solution of BPA in aqueous sodium hydroxide(prepared by dissolving 27.75 g of BPA in an aqueous solution preparedby dissolving 14.9 g of NaOH and 55 mg of sodium dithionite in 219 mL ofwater) were added to the polymerization liquid, and the mixture wassubjected to a polymerization reaction for 50 minutes. 95 mL ofmethylene chloride was added to the resultant for dilution and thediluted product was stirred for 10 minutes.

(2) Polymerization Liquid-Separating Step

The polymerization liquid thus obtained was filled into a cylindricalglass vessel having an inner diameter of 4.2 cm and a height of 40 cm.After a lapse of a predetermined time, an organic phase (methylenechloride solution containing the polycarbonate-polyorganosiloxanecopolymer) at a position corresponding to a height of 20 cm from thebottom was collected, and a water content in the organic phase wasmeasured by the method. A relational expression between an elapsed timeand the remaining water content in the organic phase was determined byplotting the remaining water content in the organic phase at eachelapsed time, and a time (min) required for the water content in theorganic phase to reach 2.8 mass % was determined from the relationalexpression.

After that, the total amount of the organic phase was collected andcentrifuged with a centrifuge (“CF6L” manufactured by Hitachi Koki Co.,Ltd.) at 3,000 rpm for 5 minutes, followed by the removal of separatedwater. Thus, an organic phase was obtained.

(3) Aqueous NaOH Washing Step

0.03 mol/L Aqueous NaOH was added to the organic phase obtained in thepolymerization liquid-separating step so that the content of the aqueousphase became 15 vol %, and the mixture was stirred at 350 rpm for 10minutes. The solution obtained after the stirring was filled into acylindrical glass vessel having an inner diameter of 4.2 cm and a heightof 40 cm. After a lapse of a predetermined time, an organic phase(methylene chloride solution containing thepolycarbonate-polyorganosiloxane copolymer) at a position correspondingto a height of 20 cm from the bottom was collected, and a water contentin the organic phase was measured by the method. A relational expressionbetween an elapsed time and the remaining water content in the organicphase was determined by plotting the remaining water content in theorganic phase at each elapsed time, and a time (min) required for thewater content in the organic phase to reach 1.5 mass % was determinedfrom the relational expression.

After that, the total amount of the organic phase was collected andcentrifuged with a centrifuge (“CF6L” manufactured by Hitachi Koki Co.,Ltd.) at 3,000 rpm for 5 minutes, followed by the removal of separatedwater. Thus, an organic phase was obtained.

(4) Aqueous HCl Washing Step

0.2 mol/L Aqueous HCl was added to the organic phase obtained in theaqueous NaOH washing step so that the content of the aqueous phasebecame 15 vol %, and the mixture was stirred at 500 rpm for 10 minutes.The solution obtained after the stirring was filled into a cylindricalglass vessel having an inner diameter of 4.2 cm and a height of 40 cm.After a lapse of a predetermined time, an organic phase (methylenechloride solution containing the polycarbonate-polyorganosiloxanecopolymer) at a position corresponding to a height of 20 cm from thebottom was collected, and a water content in the organic phase wasmeasured by the method. A relational expression between an elapsed timeand the remaining water content in the organic phase was determined byplotting the remaining water content in the organic phase at eachelapsed time, and a time (min) required for the water content in theorganic phase to reach 1.5 mass % was determined from the relationalexpression.

After that, the total amount of the organic phase was collected andcentrifuged with a centrifuge (“CF6L” manufactured by Hitachi Koki Co.,Ltd.) at 3,000 rpm for 5 minutes, followed by the removal of separatedwater. Thus, an organic phase was obtained.

(5) Pure Water Washing Step

Pure water was added to the organic phase obtained in the aqueous HClwashing step so that the content of the aqueous phase became 15 vol %,and the mixture was stirred at 500 rpm for 10 minutes. The solutionobtained after the stirring was filled into a cylindrical glass vesselhaving an inner diameter of 4.2 cm and a height of 30 cm. After a lapseof a predetermined time, an organic phase (methylene chloride solutioncontaining the polycarbonate-polyorganosiloxane copolymer) at a positioncorresponding to a height of 20 cm from the bottom was collected, and awater content in the organic phase was measured by the method. Arelational expression between an elapsed time and the remaining watercontent in the organic phase was determined by plotting the remainingwater content in the organic phase at each elapsed time, and a time(min) required for the water content in the organic phase to reach 1.5mass % was determined from the relational expression.

After that, the total amount of the organic phase was collected andcentrifuged with a centrifuge (“CF6L” manufactured by Hitachi Koki Co.,Ltd.) at 3,000 rpm for 5 minutes, followed by the removal of separatedwater. Thus, an organic phase was obtained.

Examples 8 to 12, and Comparative Examples 3 and 4

Copolymers were each produced in the same manner as in Example 7 exceptthat in Example 7, any one of the PDMS-2 to the PDMS-8 was used insteadof the PDMS-1, washing and oil-water separation were performed, and atime required for a water content in an organic phase to reach apredetermined value in each step was determined. The results are shownin Table 2.

TABLE 2 Example Comparative Example 7 8 9 10 11 12 3 4 PDMS PDMS-1PDMS-2 PDMS-3 PDMS-4 PDMS-5 PDMS-6 PDMS-7 PDMS-8 Polymerizationliquid-separating step (min) 50 55 55 60 60 70 85 80 (Water content: 2.8mass %) *1 NaOH washing/separating step (min) 67 70 60 75 80 80 110 100(Water content: 1.5 mass %) *1 Hydrochloric acid washing/separating step(min) 35 40 65 65 50 75 115 95 (Water content: 1.5 mass %) *1 Pure waterwashing/separating step (min) 50 50 35 60 50 40 50 50 (Water content:1.5 mass %) *1 Total separation time in all separating steps (min) 202215 215 260 240 265 360 325 Viscosity-average molecular weight Mv ofPC-POS 18,000 17,700 17,300 17,300 17,500 18,100 18,100 18,100 copolymer*1: A time (min) required to reach a predetermined water content in anorganic phase in each separating step

As can be seen from the results of Table 2, when apolycarbonate-polyorganosiloxane copolymer is produced by using thepolyorganosiloxane produced by the method of the present invention, anoil-water separation rate in the step of purifying thepolycarbonate-polyorganosiloxane copolymer is high.

INDUSTRIAL APPLICABILITY

According to the method of the present invention, a polyorganosiloxanewhose transition metal content, especially platinum content is small canbe efficiently produced. When the polyorganosiloxane obtained by thepresent invention is used, an oil-water separation rate in the step ofpurifying a polycarbonate-polyorganosiloxane copolymer is high, andhence the polycarbonate-polyorganosiloxane copolymer can be efficientlyproduced.

1. A method of producing a polyorganosiloxane, comprising bringing apolyorganosiloxane produced by using a transition metal-based catalystinto contact with an adsorbent having an average pore diameter of 1,000Å or less.
 2. The method of producing a polyorganosiloxane according toclaim 1, wherein the adsorbent comprises a porous adsorbent.
 3. Themethod of producing a polyorganosiloxane according to claim 1, whereinthe adsorbent comprises at least one selected from the group consistingof activated clay, acid clay, activated carbon, a synthetic zeolite, anatural zeolite, activated alumina, silica, and a silica-magnesia-basedadsorbent.
 4. The method of producing a polyorganosiloxane according toclaim 1, wherein the polyorganosiloxane is represented by the followinggeneral formula (1-1):

wherein R¹ to R⁴ each independently represent a hydrogen atom, a halogenatom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, Yrepresents a single bond, or an organic residue containing an aliphaticor aromatic moiety, the organic residue being bonded to Si and O or toSi and Z, n represents an average number of repetitions, m represents 0or 1, Z each independently represent a halogen, —R⁵OH, —R⁵COOH, —R⁵NH₂,—R⁵NHR⁶, —COOH, or —SH, R⁵ represents a linear, branched, or cyclicalkylene group, an aryl-substituted alkylene group, an aryl-substitutedalkylene group which may have an alkoxy group on a ring thereof, or anarylene group, and R⁶ represents an alkyl group, an alkenyl group, anaryl group, or an aralkyl group.
 5. The method of producing apolyorganosiloxane according to claim 4, wherein R¹ to R⁴ eachindependently represent a hydrogen atom, an alkyl group having 1 to 6carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an arylgroup having 6 to 12 carbon atoms, and Z each independently represent—R⁵OH, —R⁵COOH, —R⁵NH₂, —R⁵NHR⁶, —COOH, or —SH.
 6. The method ofproducing a polyorganosiloxane according to claim 1, wherein thepolyorganosiloxane is represented by the following general formula (1-2)or (1-4):

wherein R¹ to R⁴ each independently represent a hydrogen atom, a halogenatom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, nrepresents an average number of repetitions, and a represents a positiveinteger.
 7. The method of producing a polyorganosiloxane according toclaim 4, wherein R¹ to R⁴ each represent a methyl group.
 8. Apolyorganosiloxane, which is produced by the method of claim 1, thepolyorganosiloxane having a platinum content of 1 ppm by mass or less.9. A polycarbonate-polyorganosiloxane copolymer, which is produced byusing the polyorganosiloxane of claim
 8. 10. Thepolycarbonate-polyorganosiloxane copolymer according to claim 9, whereinthe polycarbonate-polyorganosiloxane copolymer comprises apolyorganosiloxane moiety as a repeating unit having a structurerepresented by the following general formula (I) and a polycarbonatemoiety as a repeating unit having a structure represented by thefollowing general formula (II):

wherein R¹¹ to R¹⁴ each independently represent a hydrogen atom, ahalogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy grouphaving 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbonatoms, Y¹ represents a single bond, or an organic residue containing analiphatic or aromatic moiety, n1 represents an average number ofrepetitions, R²¹ and R²² each independently represent a halogen atom, analkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6carbon atoms, X represents a single bond, an alkylene group having 1 to8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, acycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene grouphaving 5 to 15 carbon atoms, a fluorenediyl group, an arylalkylene grouphaving 7 to 15 carbon atoms, an arylalkylidene group having 7 to 15carbon atoms, —S—, —SO—, —SO₂—, —O—, or —CO—, and b and c eachindependently represent an integer of 0 to 4.